编写脚本时是否可以同时计算所有值? [英] Is it possible to compute all the values at the same time when writing a script?

问题描述

定义功能时，说TEST = @(t) t.^2.如果输入是向量，请说[1,2,3,4]，TEST([1,2,3,4]) = [1,4,9,16].

When defining a function, say TEST = @(t) t.^2. If the input is a vector, say [1,2,3,4], TEST([1,2,3,4]) = [1,4,9,16].

如果定义的函数采用脚本形式，我们可以做类似的事情吗?我的意思是，如果我有脚本，请说TEST.m，这样ret = TEST(x,y,z)会在知道x，y和z的数值时输出一个值.假设当x，y固定时，假设分别为0、1，我想计算100个不同的z值，范围从1到100.是否可以输出TEST(0,1,1:1:100)而无需编写for循环或更改脚本TEST.m的任何内容?

Can we do similar thing if the function defined is in script form? What I mean is that if I have a script, say TEST.m such that ret = TEST(x,y,z) which outputs a value when knowing numerical values of x, y and z. Suppose I want to calculate 100 different values of z ranging from 1 to 100 when x, y are fixed, say at 0, 1 respectively. Is it possible to output TEST(0,1,1:1:100) without writing a for loop or changing any contents of the script TEST.m?

问这样的问题的原因来自于计算时间.通常，我拥有的脚本可能有点复杂，因此单个值的计算可能要花几分钟的时间.编写for循环以输出它会非常耗时.我想编写parfor循环，但是对于我来说，计算时间仍然很长，无法继续使用.我想知道是否可以一次计算所有100个值.我是程序员的入门者，我希望在这篇文章之后能得到满意的答复.感谢您的所有帮助.

The reason to ask such question comes from the computation time. Usually, the script I have may be a little complicated so that the calculate of a single value may take few minutes to go. Writing for-loop to output it can be very time-consuming. I think of writing parfor loop, but the computation time is still long to me for further uses. I wonder if I can calculate all the 100 values at a time. I am a starter of programmer, and I hope I can get satisfactory answers after this post. Thanks for all your help.

推荐答案

您可以定义一个新的匿名函数，以获取固定值作为参数，并获取矢量作为输入.然后使用arrayfun对数组的所有值进行计算.

You cab define a new anonymous function to get the fixed values as parameters, and the vector as input. Then use arrayfun to compute it on all values of the array.

假设您具有以下功能:

function ret = TEST(x,y,z)
    ret = f(x)+g(y)+h(z);
end

function r = f(x)
r = x^2;
end

function r = g(y)
r = y^3;
end

function r = h(z)
r = z^4;
end

您从以下位置调用它:

x = 2;
y = 3;
z = 1:5;
T = @(z) TEST(x,y,z);
arrayfun(T,z)

所以T是一个新函数，将x和y视为常量，并且仅以z作为输入.然后arrayfun取T并为z中的每个元素进行计算，您将得到:

So T is a new function that treat x and y as constants, and only have z as input. Then arrayfun takes T and compute it for every element in z, and you get:

ans =

    32    47   112   287   656

现在，如果x和y可以保持不变，则可以将arrayfun与更多的矢量一起使用，例如[a,b,c] = arrayfun(T,z,w,v).

Now, you can use arrayfun with more vectors, like [a,b,c] = arrayfun(T,z,w,v), if x and y can stay constant.

希望它能回答您的问题；)

Hopes it answers your question ;)

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